The present invention relates to a process for preparing EDDN and/or EDMN by conversion of FA, HCN and EDA, the conversion being effected in the presence of water and the water being depleted by distillation on completion of conversion from the reaction mixture. The present invention also relates to the preparation of TETA and/or DETA by reaction of EDDN or EDMN with hydrogen in the presence of a catalyst wherein water is depleted by distillation after the preparation. The present invention further provides for the preparation of epoxy resins, amides or polyamides from the DETA or TETA obtained in accordance with the invention.
WO 2008/104579 and the prior art cited in WO 2008/104579 specify various preparation methods for EDDN and EDMN.
In WO 2008/104579, EDDN is prepared by reacting EDA with formaldehyde (FA) and hydrogen cyanide (HCN) with a molar ratio of EDA to FA to HCN of 1:1.5:1.5 to 1:2:2 [mol:mol:mol]. The preparation can be effected by a) reacting EDA with FACH with a molar ratio of EDA to FACH of 1:1.5 to 1:2, or b) preparing EDDN by reaction of an ethylenediamine-formaldehyde adduct (EDFA) with hydrogen cyanide with a molar ratio of EDFA to HCN of 1:1.5 to 1:2, or c) reacting EDA with a mixture of formaldehyde and hydrogen cyanide with a molar ratio of EDA to FA to HCN of 1:1.5:1.5 to 1:2:2, or d) reacting EDA simultaneously with formaldehyde and HCN with a molar ratio of EDA to FA to HCN of 1:1.5:1.5 to 1:2:2.
It is disclosed that these reactions are preferably performed at a temperature of 10 to 90° C. and at standard pressure to slightly elevated super-atmospheric pressure. Preferred reactors are described as being a tubular reactor or a stirred tank cascade. The reaction output formed is preferably worked up by distillation, first removing low boilers such as hydrogen cyanide in a first stage and removing water in a second distillation step. The remaining aminonitrile mixture may have a residual water content of preferably at least 10% by weight.